someone who leeches off new popularity. may actually like the stuff, (like mcr when loads of people liked the black parade) but wears and listens to other things because people wear or listen to it.
they may actually be emo, but because they like mcr they think they have to wear stuff that they wouldn't wear anyway
there are real emos but loads are just kids who wanna be emo beacause they think there better than non emos because they think theyve herd something new that know else has heard.

poser1: o my god! heard the new mcr song? it the best one of the album.
poser3: do ya know them studded belts? im gonna get one because gerrard was wearin one.
poser 4: them emo sk8er bois over there are so cute. i love emo bois with side fringes and hoodies!
normal person: i dont like mcr but atleast i know enought to say they have 3 albums apart from you posers who just think the black parade is there first one.

The Urban Dictionary T-Shirt

Any one who does not follow his/her own ideas of what he/she likes. Following no one set norm makes you real and following no one set norm makes you poser. Poser is governed not by the clothes, music, or makeup you wear, but rather by the state of your mind and the conformity to your own beliefs.

The Urban Dictionary T-Shirt

a person - usually in middle or high school, who is insecure about him/herself and trys very hard not to be a "conformist" or a "prep," by doing things like: purchasing a skateboard or guitar, purchasing a great deal of clothing and accessories from hot topic, and listening to pop-punk bands such as simple plan, yellowcard, etc. usually, this supposedly "nonconformist" behavior just backfires on him/her, because now he/she is still conforming, just to a different group of people. so the moral of the story is to be yourself.

The Urban Dictionary T-Shirt

Someone whos acts like someone theyre not,but not realizing that there being fake, basically a loser trying to fit in.

A poser green day fan,this applies to other poser bands--
Todd:have you heard american idiot?Thats the bestest song ever!
Bill:Have u even heard any other green day songs?
Todd:what other green day songs?

The Urban Dictionary T-Shirt

A poser is someone who tries hard to be something they arent. Usually, posers call other people posers because they are jealous that the person they called a poser is more skater/stoner/goth/punk/rocker/grunge/etc. than they will ever be.